t1300: don't create unused files

t1300: don't create unused files

Three tests in t1300-config.sh check that "git config --get" barfs when
syntax errors are present in the config file.  The tests redirect
standard output and standard error of "git config --get" to files,
"actual" and "error" correspondingly.  They assert presence of an error
message in file "error".  However, these tests don't use file "actual"
for assertions.

Don't redirect standard output of "git config --get" to file "actual" in
t1300-config.sh to avoid creating unnecessary files.

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>